From 3dbd0e57bae0dbe2a3f2c006fb767417a2c5419e Mon Sep 17 00:00:00 2001 From: Andrew Murray Date: Mon, 10 Mar 2025 10:14:38 +1100 Subject: [PATCH] Added DXT1 encoding --- Tests/test_file_dds.py | 31 ++++++- setup.py | 1 + src/PIL/DdsImagePlugin.py | 61 ++++++++----- src/_imaging.c | 3 + src/encode.c | 18 ++++ src/libImaging/BcnEncode.c | 173 +++++++++++++++++++++++++++++++++++++ src/libImaging/Imaging.h | 2 + 7 files changed, 262 insertions(+), 27 deletions(-) create mode 100644 src/libImaging/BcnEncode.c diff --git a/Tests/test_file_dds.py b/Tests/test_file_dds.py index 7cc4d79d4..7a6099ce7 100644 --- a/Tests/test_file_dds.py +++ b/Tests/test_file_dds.py @@ -9,7 +9,12 @@ import pytest from PIL import DdsImagePlugin, Image -from .helper import assert_image_equal, assert_image_equal_tofile, hopper +from .helper import ( + assert_image_equal, + assert_image_equal_tofile, + assert_image_similar_tofile, + hopper, +) TEST_FILE_DXT1 = "Tests/images/dxt1-rgb-4bbp-noalpha_MipMaps-1.dds" TEST_FILE_DXT3 = "Tests/images/dxt3-argb-8bbp-explicitalpha_MipMaps-1.dds" @@ -389,5 +394,25 @@ def test_save(mode: str, test_file: str, tmp_path: Path) -> None: assert im.mode == mode im.save(out) - with Image.open(out) as reloaded: - assert_image_equal(im, reloaded) + assert_image_equal_tofile(im, out) + + +def test_save_dxt1(tmp_path: Path) -> None: + out = str(tmp_path / "temp.dds") + with Image.open(TEST_FILE_DXT1) as im: + im.convert("RGB").save(out, pixel_format="DXT1") + assert_image_similar_tofile(im, out, 1.84) + + im_alpha = im.copy() + im_alpha.putpixel((0, 0), (0, 0, 0, 0)) + im_alpha.save(out, pixel_format="DXT1") + with Image.open(out) as reloaded: + assert reloaded.getpixel((0, 0)) == (0, 0, 0, 0) + + im_l = im.convert("L") + im_l.save(out, pixel_format="DXT1") + assert_image_similar_tofile(im_l.convert("RGBA"), out, 9.25) + + im_alpha.convert("LA").save(out, pixel_format="DXT1") + with Image.open(out) as reloaded: + assert reloaded.getpixel((0, 0)) == (0, 0, 0, 0) diff --git a/setup.py b/setup.py index a85731db9..9fac993b1 100644 --- a/setup.py +++ b/setup.py @@ -68,6 +68,7 @@ _LIB_IMAGING = ( "Reduce", "Bands", "BcnDecode", + "BcnEncode", "BitDecode", "Blend", "Chops", diff --git a/src/PIL/DdsImagePlugin.py b/src/PIL/DdsImagePlugin.py index cdae8dfee..718f376e8 100644 --- a/src/PIL/DdsImagePlugin.py +++ b/src/PIL/DdsImagePlugin.py @@ -518,30 +518,43 @@ def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None: msg = f"cannot write mode {im.mode} as DDS" raise OSError(msg) - alpha = im.mode[-1] == "A" - if im.mode[0] == "L": - pixel_flags = DDPF.LUMINANCE - rawmode = im.mode - if alpha: - rgba_mask = [0x000000FF, 0x000000FF, 0x000000FF] - else: - rgba_mask = [0xFF000000, 0xFF000000, 0xFF000000] - else: - pixel_flags = DDPF.RGB - rawmode = im.mode[::-1] - rgba_mask = [0x00FF0000, 0x0000FF00, 0x000000FF] - - if alpha: - r, g, b, a = im.split() - im = Image.merge("RGBA", (a, r, g, b)) - if alpha: - pixel_flags |= DDPF.ALPHAPIXELS - rgba_mask.append(0xFF000000 if alpha else 0) - - flags = DDSD.CAPS | DDSD.HEIGHT | DDSD.WIDTH | DDSD.PITCH | DDSD.PIXELFORMAT + flags = DDSD.CAPS | DDSD.HEIGHT | DDSD.WIDTH | DDSD.PIXELFORMAT bitcount = len(im.getbands()) * 8 - pitch = (im.width * bitcount + 7) // 8 + raw = im.encoderinfo.get("pixel_format") != "DXT1" + if raw: + codec_name = "raw" + flags |= DDSD.PITCH + pitch = (im.width * bitcount + 7) // 8 + alpha = im.mode[-1] == "A" + if im.mode[0] == "L": + pixel_flags = DDPF.LUMINANCE + rawmode = im.mode + if alpha: + rgba_mask = [0x000000FF, 0x000000FF, 0x000000FF] + else: + rgba_mask = [0xFF000000, 0xFF000000, 0xFF000000] + else: + pixel_flags = DDPF.RGB + rawmode = im.mode[::-1] + rgba_mask = [0x00FF0000, 0x0000FF00, 0x000000FF] + + if alpha: + r, g, b, a = im.split() + im = Image.merge("RGBA", (a, r, g, b)) + if alpha: + pixel_flags |= DDPF.ALPHAPIXELS + rgba_mask.append(0xFF000000 if alpha else 0) + + fourcc = 0 + else: + codec_name = "bcn" + flags |= DDSD.LINEARSIZE + pitch = (im.width + 3) * 4 + rawmode = None + rgba_mask = [0, 0, 0, 0] + pixel_flags = DDPF.FOURCC + fourcc = D3DFMT.DXT1 fp.write( o32(DDS_MAGIC) + struct.pack( @@ -556,11 +569,11 @@ def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None: ) + struct.pack("11I", *((0,) * 11)) # reserved # pfsize, pfflags, fourcc, bitcount - + struct.pack("<4I", 32, pixel_flags, 0, bitcount) + + struct.pack("<4I", 32, pixel_flags, fourcc, bitcount) + struct.pack("<4I", *rgba_mask) # dwRGBABitMask + struct.pack("<5I", DDSCAPS.TEXTURE, 0, 0, 0, 0) ) - ImageFile._save(im, fp, [ImageFile._Tile("raw", (0, 0) + im.size, 0, rawmode)]) + ImageFile._save(im, fp, [ImageFile._Tile(codec_name, (0, 0) + im.size, 0, rawmode)]) def _accept(prefix: bytes) -> bool: diff --git a/src/_imaging.c b/src/_imaging.c index fa38dcc05..330a7eef4 100644 --- a/src/_imaging.c +++ b/src/_imaging.c @@ -4041,6 +4041,8 @@ PyImaging_ZipDecoderNew(PyObject *self, PyObject *args); /* Encoders (in encode.c) */ extern PyObject * +PyImaging_BcnEncoderNew(PyObject *self, PyObject *args); +extern PyObject * PyImaging_EpsEncoderNew(PyObject *self, PyObject *args); extern PyObject * PyImaging_GifEncoderNew(PyObject *self, PyObject *args); @@ -4109,6 +4111,7 @@ static PyMethodDef functions[] = { /* Codecs */ {"bcn_decoder", (PyCFunction)PyImaging_BcnDecoderNew, METH_VARARGS}, + {"bcn_encoder", (PyCFunction)PyImaging_BcnEncoderNew, METH_VARARGS}, {"bit_decoder", (PyCFunction)PyImaging_BitDecoderNew, METH_VARARGS}, {"eps_encoder", (PyCFunction)PyImaging_EpsEncoderNew, METH_VARARGS}, {"fli_decoder", (PyCFunction)PyImaging_FliDecoderNew, METH_VARARGS}, diff --git a/src/encode.c b/src/encode.c index 13d5cdaf7..d27783f0c 100644 --- a/src/encode.c +++ b/src/encode.c @@ -350,6 +350,24 @@ get_packer(ImagingEncoderObject *encoder, const char *mode, const char *rawmode) return 0; } +/* -------------------------------------------------------------------- */ +/* BCN */ +/* -------------------------------------------------------------------- */ + +PyObject * +PyImaging_BcnEncoderNew(PyObject *self, PyObject *args) { + ImagingEncoderObject *encoder; + + encoder = PyImaging_EncoderNew(0); + if (encoder == NULL) { + return NULL; + } + + encoder->encode = ImagingBcnEncode; + + return (PyObject *)encoder; +} + /* -------------------------------------------------------------------- */ /* EPS */ /* -------------------------------------------------------------------- */ diff --git a/src/libImaging/BcnEncode.c b/src/libImaging/BcnEncode.c new file mode 100644 index 000000000..42a46358c --- /dev/null +++ b/src/libImaging/BcnEncode.c @@ -0,0 +1,173 @@ +/* + * The Python Imaging Library + * + * encoder for DXT1-compressed data + * + * Format documentation: + * https://web.archive.org/web/20170802060935/http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_compression_s3tc.txt + * + */ + +#include "Imaging.h" + +#include "Bcn.h" + +typedef struct { + UINT8 color[3]; +} rgb; + +typedef struct { + UINT8 color[3]; + int alpha; +} rgba; + +static rgb +decode_565(UINT16 x) { + rgb item; + int r, g, b; + r = (x & 0xf800) >> 8; + r |= r >> 5; + item.color[0] = r; + g = (x & 0x7e0) >> 3; + g |= g >> 6; + item.color[1] = g; + b = (x & 0x1f) << 3; + b |= b >> 5; + item.color[2] = b; + return item; +} + +static UINT16 +encode_565(rgba item) { + UINT8 r, g, b; + r = item.color[0] >> (8 - 5); + g = item.color[1] >> (8 - 6); + b = item.color[2] >> (8 - 5); + return (r << (5 + 6)) | (g << 5) | b; +} + +int +ImagingBcnEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) { + UINT8 *dst = buf; + + for (;;) { + int i, j, k; + UINT16 color_min = 0, color_max = 0; + rgb color_min_rgb, color_max_rgb; + rgba block[16], *current_rgba; + + // Determine the min and max colors in this 4x4 block + int has_alpha_channel = + strcmp(im->mode, "RGBA") == 0 || strcmp(im->mode, "LA") == 0; + int first = 1; + int transparency = 0; + for (i = 0; i < 4; i++) { + for (j = 0; j < 4; j++) { + int x = state->x + i * im->pixelsize; + int y = state->y + j; + if (x >= state->xsize * im->pixelsize || y >= state->ysize) { + // The 4x4 block extends past the edge of the image + continue; + } + + current_rgba = &block[i + j * 4]; + for (k = 0; k < 3; k++) { + current_rgba->color[k] = + (UINT8)im->image[y][x + (im->pixelsize == 1 ? 0 : k)]; + } + if (has_alpha_channel) { + if ((UINT8)im->image[y][x + 3] == 0) { + current_rgba->alpha = 0; + transparency = 1; + continue; + } else { + current_rgba->alpha = 1; + } + } + + UINT16 color = encode_565(*current_rgba); + if (first || color < color_min) { + color_min = color; + } + if (first || color > color_max) { + color_max = color; + } + first = 0; + } + } + + if (transparency) { + *dst++ = color_min; + *dst++ = color_min >> 8; + } + *dst++ = color_max; + *dst++ = color_max >> 8; + if (!transparency) { + *dst++ = color_min; + *dst++ = color_min >> 8; + } + + color_min_rgb = decode_565(color_min); + color_max_rgb = decode_565(color_max); + for (i = 0; i < 4; i++) { + UINT8 l = 0; + for (j = 3; j > -1; j--) { + current_rgba = &block[i * 4 + j]; + if (transparency && !current_rgba->alpha) { + l |= 3 << (j * 2); + continue; + } + + float distance = 0; + int total = 0; + for (k = 0; k < 3; k++) { + float denom = + (float)abs(color_max_rgb.color[k] - color_min_rgb.color[k]); + if (denom != 0) { + distance += + abs(current_rgba->color[k] - color_min_rgb.color[k]) / + denom; + total += 1; + } + } + if (total == 0) { + continue; + } + distance *= 6 / total; + if (transparency) { + if (distance < 1.5) { + // color_max + } else if (distance < 4.5) { + l |= 2 << (j * 2); // 1/2 * color_min + 1/2 * color_max + } else { + l |= 1 << (j * 2); // color_min + } + } else { + if (distance < 1) { + l |= 1 << (j * 2); // color_min + } else if (distance < 3) { + l |= 3 << (j * 2); // 1/3 * color_min + 2/3 * color_max + } else if (distance < 5) { + l |= 2 << (j * 2); // 2/3 * color_min + 1/3 * color_max + } else { + // color_max + } + } + } + *dst++ = l; + } + + state->x += im->pixelsize * 4; + + if (state->x >= state->xsize * im->pixelsize) { + state->x = 0; + state->y += 4; + if (state->y >= state->ysize) { + state->errcode = IMAGING_CODEC_END; + break; + } + } + } + + return dst - buf; +} diff --git a/src/libImaging/Imaging.h b/src/libImaging/Imaging.h index 0c2d3fc2e..0fc191d15 100644 --- a/src/libImaging/Imaging.h +++ b/src/libImaging/Imaging.h @@ -567,6 +567,8 @@ typedef int (*ImagingCodec)( extern int ImagingBcnDecode(Imaging im, ImagingCodecState state, UINT8 *buffer, Py_ssize_t bytes); extern int +ImagingBcnEncode(Imaging im, ImagingCodecState state, UINT8 *buffer, int bytes); +extern int ImagingBitDecode(Imaging im, ImagingCodecState state, UINT8 *buffer, Py_ssize_t bytes); extern int ImagingEpsEncode(Imaging im, ImagingCodecState state, UINT8 *buffer, int bytes);